Fuel injection apparatus



Dec. 45', 1953 o. FRENCH 2,662,476

FUEL INJECTION APPARATUS Filed June 8, 1950 INVENTOR.

Patented Dec. 15, 1953 UNITED STATES PATEN T GF F 'I C E 062,476 FUEL INJECTION'AFPARATUS Louis ti'iich, Milwaukee, n ipucatioiriuh'es, 1950, sm-a so. "ie'tiiis testin (china- 4 1) The invention relates to fuel injection 'apparahis and more particularly to compression pressure operated fuel injection apparatus.

The main objector" the invention is to provide a unit injector or combinedfhigh pressure fuel pump and sprayer .of simple construc'tionof the type in which the fuel-pump plunger is directly operated by a compression pressure operated actuating piston mounted in a cylinder on the top of the injector housing. U y

A further object of the invention is to provide a unit-injector of the type above described formed to provide cooling spaces for the pump body and the cylinder of the operating pistonlinwhich the fuel :issuccessivelylpassed through said spaces and in which the actuating piston and its cylinder forms w a pump. connected. by :a. check .valve .4 and acrelief valve with the cooling Space .ofitsc'cylinder and acting as a coolant pump v:for internal cooling of the actuating piston and also as a control for the movement ofisai'd piston, l

A further object .of theinvention is to provide a unit injector and a compression pressureoperated actuator therefor including an actuating piston and its cylinder which fuel, from a supply pipe is usedto supply the injector, co'ol both the injector housing and said cylinder, andserve as a coolant for the interior pf,the. operating ni tomasa cush o ,medium for takinglthe sh ck inc d n tqst ppins the. m v ment said piston, as a control fluid for the timing oi the beginningof injection-;and asa lubricantiior the actuating piston; the fuel being continuously circulated through the injector housing and the actuator =cyii'nder, 1 The invention further consists in the several featureshereinafter set forth and more partiedlarly defined by claims at the conclusion here of.

In thedrawin'gs: c r n a Fig, 1 is a vertical sectional viewthrough fuel injection apparatus embodying the invention taken on theline l'l of Fig; 3; parts being broken away; i V V V Fig. 2 is a vertical sectional view taken on the line 2-2.0i Fig: 3; V a, Fig; 3 is a horizontal sectional view taken on the line 3-3 of'Figll; l l. M

Fig; 4 ista detailed sectional view showing certain modifications; Referring to the drawings, the numeral 5 designates generally the injector housing or casing here shown as formed of an upper part 6, and a lower part I, 8 the cylinder ofv the compression pressure operated actuator; 9 the actuating or pa ties nifoiintedin the bore, with is flange perating piston Working in the cylinder :8, and 1h a fpfa rtition between "the housing 5 fari'd the cylinder 8. 'lhe partition 'fll has fla't faced fluidt ntspumng e gagement with the base or the cylinder ii on one side and the top-of the houss. 5 o i th r. iam se a e. be new shown as a sleeve member having concentric dif The. i z l f i thesi t o gh t e rim na bores23 and]; into the conicaljbor'e g! and seats 9a the s ou er wl il medbb t een the hores 23 t e iii l fi e an we e n zzl antes an exam e, I have. awn the i lel em i l a l ro d d w t q m h ri' bores 29, 3D, and 3|; A valve seat "membersz in theforrnof afianged sleeve has its tubulas at abutting the gap or m m fiandanother awe; seat member 33in the Qfornrof a flanged s'l a at H flange abutting e,0.f, saidm fiiber Gi m rited n t e screen an n ar r and m mb s? 99 I I of said valve having flats or recesses fuel clearance A fiat faced disk check is mounted in th e bore of sle ves:

t e sea m mber 3 iii ge if 1 1 ck his fue e e r flat tor oov an i above the valve 31 by a projection 40 on said valve.

The lower end of the pump barrel l4 seats on the top of seat member 33, and its upper end of reduced diameter fits in the bore 21 and seats against the shoulder formed between the bores 25 and 21. The barrel 14 has inlet and relief ports 42 controlled by the plunger 16 and connected with fuel grooves 43 and 44. The lower end of the barrel is spaced from bore 2! to form a coolant space 45 surrounding the discharge valving. A portion of the upper end of the barrel [9 is spaced from the lower end of the part to form a coolant space 48.

The part 5 has an inlet conduit 41 which at its upper end communicates with a passage 49 in the partition ii! that connects with an inlet passage 49 in the base of the cylinder 8 which connects with a passage including an inlet fitting 59 and a strainer 5|. The conduit 41 leads to the coolant space 55 which is connected with the space 45 by the groove 43 in the barrel. The groove 44 in the barrel is connected at one end with the space 45 and at its other end communicates with a short pipe 52 anchored in the part 6 and extending into a notch 53 in the barrel to key the barrel to the body or casing 5. The pipe 52 forms the inner end of a fuel return conduit 54 which connects with alined passages 55 and 56 in the partition l9 and cylinder 8, respectively, the passage 55 discharging into a coolant or jacket space 5'! which has an outlet 58 at its upper end.

The cylinder 8 has a centrally disposed bore 59 in which the operating piston 9 works. A passage 68 connects with the central portion of the top of the bore 5i against which the valved piston 9 seats. The piston rings 63 are mounted in a groove in the piston, one side of which is formed by the head end 52 which has threaded connection with a centrally disposed threaded stud 54 projecting from the main body of the piston, a lock washer 55 being mounted between the two piston parts. The piston 9 also has a very shallow groove 55 formed therein adapted to communicate with a port 61 communicating with the jacket space 51, so that if any gases leak by the rings 53, they will find their way out into the jacket 51 and be carried away through the fuel return which may include a suitable separator. Also this groove will act as a lubricant groove to receive fuel from the space 51 to lubricate the rings 83, this groove preferably being not more than one-thousandth of an inch in depth.

The piston 9 is returned and normally held in its outer or upper position by a spring 58 interposed between the partition H] and a washer 59 abutting the inner side of said piston, said washer being split to receive the upper flanged end of the plunger H5.

The partition it) may be a one piece member having a flat disk portion 58 and a centrally disposed tubular portion 1 I, but to facilitate grinding and finishing operations the portions 19 and H are preferably made as separate pieces, the portion 19 being a plain flat disk and the tube H being provided with an annular shoulder 12 and a threaded end '23 to receive a clamping nut 14 by which the disk is clamped between it and said shoulder.

The stem of the plunger is mounted with a close sliding fit in the bore of the tube H and may be provided with an O-ring to further prevent leakage from the interior of the cylinder 8. The stem has flats =6 slidably engaging the flat sides of a centrally disposed opening in a and has a valve seat portion 3 head end 52 of the f pinion H which is mounted in the bore 25 in the top of the part 6 in which the nut 14 is also mounted. The pinion meshes with a rack 18 that works in a guide slot in the part 5.

Metering of the fuel is accomplished by rotating or angularly shifting the position of the plunger 15. As herein shown, the plunger I6 itself is a metering member cooperating with the orts 42, said plunger being recessed and grooved to provide a control edge 19 and a pas sage 89 communicating with an annular recess 8| whereby as the plunger I6 is moved relative to the ports 42, the pump chamber formed in the barrel 14 will first be cut off from said ports and sooner or later, depending upon the angular adjustment of said plunger, will be connected with one of the ports 42 when the control edge 19 passes said port. This form of metering is of the known constant stroke, by-pass controlled type. Instead of the plunger l5 being scrolled, this plunger may be a plain round rod and metering be effected by providing a scroll on the skirt of the piston 9 cooperating with a relief port in the cylinder 8 as shown, for example, in my copending application Serial No. 592,675, filed May 8, 1945, Patent No. 2,516,690, July 25, 1950, in which case the connection between the plunger l6 and the piston 9, for example an Oldham coupling, would permit angular adjustment of the piston 9 by a similar adjustment of the plunger 16.

The structure above described has been designed especially for using the compressed gases of the engine cylinder, in which the injector is mounted, as an operating fluid for the piston 9, these gases being free to move in a conduit connecting the combustion chamber C of the engine with the passage 60. This conduit may include a pipe section 82 extending through the cylinder head 83 of the engine and connected by a union coupling 84 with a pipe section 85 connected with the passage 50.

As shown in Figs. 1 and 2, the cylinder 8 has an integral head, but it may be formed with a separate head 86 clamped in fluid-tight relation with the main body of the cylinder, by a sleeve nut 81, as shown in Fig. 4, if desired. The injector may be held in the cylinder head by any suitable clamping means as, for example, a work holding in Fig. 2.

In order to supply fuel as a coolant to the interior of the cylinder 8 and also make the piston 9 function as its own coolant pump, the interior of said piston connects with the jacket space 51 through valve controlled passages. One of these passages includes connecting conduits 88, 89, and 90, the other includes connecting conduits 9|, 92, and 93. An inlet check valve 94 is mounted in the conduit 89 and normally urged by a spring 95 against its seat 95, said check valve on the suction effect of the return stroke of the piston 9 being opened to allowfuel to pass from the space 51 through conduits 88, 89, and 90 to the interior of the cylinder 8. An outlet valve 91 is mounted in the duit 92 and normally urged by a spring 98 against its flat seat 99 formed as a part of said conduit, said valve opening against its loading pressure of its spring 98 when the piston 9 is moved inwardly or downwardly on its fuel injection stroke to allow interior of the cylinder 8 through the conduits 9!, 92, and 93 back to the space 51. Thus dur ing each cycle of the injector fuel as a coolant clamp whose forks 83a are shown bore or con-' fuel to pass from the ammo is ntrooucee into the cylinder o and comes in contact with the interior of the piston s :to not to cool the "same, this fuel being taken item the supply of fuel circulating through the space 51.

Thus the valve '9"! acts as a discharge valve, but it also has another function, that or acting "as "a valve :lior varying the timing :of the lbs-g inning of the injection period and as it is formed as an adjustable relief valve. As shown, the valve 91 is a cylindrical plu g slidably zmount- 'ed in the bore of -a sleeve housing 101! having a threaded mounting in a threaded portion ililfl of the bore which at its inner end atoms the annular conduit 92. The extended end of the sleeve 1B0 is threaded to engage an adjustable threaded cap I82. The spring =98 is interposed between the outer end :of the valve 9:1 and the *cap 2 whose adjustment relative to ithe sleeve determines the tension in-g pr loading of the spring 9 6. With this construction when the :compression pressure of the gases in the combustion chamber C reach a pr'edetermined value, the fuel in the cylinder 8 which acts as a coolant and 'a checking fluid will be put under 'sufiioient pressure to overcome the loading of the spring :98, so

that fuel in this cylin'der may be released and escape to the space 5-1. The loading of the spring 98 is preferably adjusted, so that the piston 9, Which acts also as a checking piston,

together with the plunger 16 begins to .move

when the working piston of the engine is within a few degrees of top dead center, for example, ten or five degrees or less. The positioning of the conduits '88 and ii! where they enter the bore 62 is preferably such that they will be lapped by the lower or checking piston end of the piston 9 just as it is completing its inward stroke, so that the body of the fuel left in the interior of the cylinder 8 Will act as a checking or cushioning fluid to check or cushion the end of the stroke of the piston 9 under the action of the gases instead of having this piston strike a metal stop to limit its movement. The final upward movement of the piston against its valve seat 6| is also preferably checked by restricting the clearance at I03 between said seat 6| and the bore 59. The restricting of the clearance at I03 as shown in the drawings also has the efiect of causing the initial injection of the fuel charge to proceed at a slower rate than when the gases operate on the whole area of the piston after the valved end 6| leaves the bore I03. This is desirable as it produces a pilot type of injection during the first part of the stroke of the plunger l6.

With the above construction fuel is continuously supplied to the injector from a suitable low pressure supply connected with the fitting 5|] and circulates, first through the injector housing, and then through the jacket space 51 and to the return pipe connected with the outlet 58. As the piston in the engine cylinder or combustion chamber C nears the end of its compression stroke, the gases tapped off from this cylinder to the cylinder 8 move the piston 9 and plunger [6 downwardly to first cut off the ports 42 and then compress the fuel in the barrel I4 ahead of the plunger l6 and force this fuel past the spring pressed check valve 31 and through the nozzle I1 and its spray orifices 28 into the combustion chamber of the engine, the amount of fuel being as heretofore noted determined by the angular adjustment of the plunger l6. When the pressures in the combustion chamber C drop to a value below the loading of the spring 68,

thisfspr ing acts to return the piston '9 and piling or 16 to their outer or upper initial positions ready for the next cycle, it being noted that dllllllg :each cycle the interior of the cylinder 8 receives a new charge or cool-ant, cushioning, "and timing fluid as :a part :of "the fuel hein'g cin- -culated through the coolant s pace I desire it to be understood that thi's i nven'tion 15 1101) to be limited-to any particular fo :rangement of ar-ts except in so far as such dim-itations are included in the claims.

What Iclaim as my invention is:

4-. In a fuel injection apparatus having a housing and pumping means in said-housin "lud lllg a pump cylinder and a plungerand a coolant space-1n said housing connected with said pump cylinder, the combination of operating means for said plunger comprising an operating *"cy lnder-mounted above said housing, an operatsa'id coolant spaces.

'2. The fuel injection apparatus defined in claim ,1 wherein the bore of said operating cylinder in which said operating piston worlss is connected to the coolant space of said operate mg cylinder by a check valve controlled inlet and by a valve controlled outlet, the above oe ifined structure acting as a coolant pump to supply fuel to said cylinder to cool the mt'erio'r of said operating piston.

The fuel injection apparatus defined within the interior of said operating piston and cylinder.

5. ln a fuel injection apparatus having a hous ng and pump means in said housing in- 6. In a fuel injection apparatus having a housing and pumping means in said housing including a pump cylinder and a plunger and a coolant chamber in said housing connected with said pump cylinder, the combination of operating means for said plunger comprising an operating cylinder mounted above said housing, a gas pressure operated piston working in said last named cylinder and operatively connected to said plunger, said operating cylinder having a coolant space, a coolant circulatory system including said coolant chamber and said coolant space and a connection with the interior of said operating cylinder, a gas relief passage also connecting the interior of said cylinder with said coolant space, and means for conducting circulating fuel through said coolant chamber and said coolant space.

7. In a unit fuel injection apparatus having a housing and pump means in said housing including a pump cylinder and a plunger, the combination of operating means for said plunger comprising an operating cylinder, a gas pressure operated piston working in said last named cylinder and operatively connected to said piston, a checking chamber in said operating cylinder inlet and outlet valve controlled passages for supplying the checking chamber of said operating cylinder with a cooling and checking fluid, and a partition mounted between said housing and said operating cylinder and forming a wall of said checking chamber and having a tubular projection extending into said operating cylinder and in which said plunger is slidably mounted.

8. In a fuel injection apparatus of the compression pressure operated type having a high pressure fuel pump having a movable element, the combination of a gas pressure operated opcrating piston operatively connected to the movable element of said pump, a cylinder in which said piston works having a gas pressure inlet, a valve seat connected with said inlet and a reduced diameter bore adjacent said valve seat, said piston having a head forming a valve cooperating with said seat and having a reduced diameter cylindrical projection fitting said reduced diameter bore during a portion of the travel of said piston relative to said cylinder to reduce the area of pressure on the piston during its initial movement to produce a pilot charge injection effect.

9. In a unit fuel injection apparatus having a housing and pump means in said housing including a pump cylinder having an inlet and a plunger, said housing having a coolant space connected with the inlet to the pump cylinder, the combination of operating means for said plunger comprising an operating cylinder associated with said housing and having a coolant space, a gas pressure operated piston working in said last named cylinder and operatively connected to said piston, and a coolant circulatory system using fuel as a coolant including the coolant spaces in said cylinders and a connection with the interior of said operating cylinder.

LOUIS O. FRENCH.

References Cited in the file of this patent UNITED STATES PATENTS 

